Method and apparatus for the purification of water contaminated with sulfate ions and with heavy metal ions

Abstract

In a device and a process for purifying water which is contaminated with sulphate ions and heavy metal ions, the water is collected in a water reservoir and a substance having basic activity in water is fed to the water reservoir in such a manner that a precipitant having heavy metal ions is precipitated from the water, wherein at least a subquantity of water is taken off from the water reservoir and is separated into pure water which is substantially freed from sulphate ions and heavy metal ions and dirty water which is enriched with sulphate ions and heavy metal ions. The dirty water is at least in part recirculated to the water reservoir, as a result of which a concentration of sulphate ions in the water reservoir is achieved such that a precipitant having sulphate ions is precipitated from the water.

What is claimed is: 
     
       1. A method for the purification of water contaminated with sulfate ions and with heavy metal ions, the method comprising:
 collecting water that accumulates in a natural water reservoir via natural drainage, the collected water being contaminated by sulfate ions and heavy metal ions via contact with the natural water reservoir; 
 supplying to the natural water reservoir a substance that interacts with contaminants in the natural water reservoir to form a first precipitation substance comprising heavy metal; 
 
       extracting from the natural water reservoir water containing the first precipitation substance and filtering the extracted water into clean water having reduced sulfate ions and heavy metal ions, and dirty water enriched with sulfate ions and heavy metal ions;
 at least partially recirculating the dirty water back into the natural water reservoir wherein the recirculated dirty water mixes with water that was not extracted from the natural water reservoir to provide a concentration of sulfate ions in the natural water reservoir that forms a second precipitation substance comprising sulfate that settles by gravity into a collecting region formed at the bottom of the natural water reservoir; and 
 physically removing at least a portion of the second precipitation substance out through the top of the collecting region of the natural water reservoir. 
 
     
     
       2. The method according to  claim 1 , comprising intermixing of contaminants in the natural water reservoir with the supplied substance. 
     
     
       3. The method according to  claim 1 , further comprising prefiltering the extracted water using a prefiltering device. 
     
     
       4. The method according to  claim 1 , wherein the extracted water is filtered into clean water and dirty water by at least one of reverse osmosis and nanofiltration. 
     
     
       5. The method according to  claim 1 , wherein the substance supplied to the natural water reservoir is a hydroxide compound. 
     
     
       6. The method according to  claim 1 , wherein the second precipitation substance is removed continuously. 
     
     
       7. The method according to  claim 1 , further comprising dewatering of the second precipitation substance physically removed from the natural water reservoir. 
     
     
       8. The method according to  claim 1 , wherein the second precipitation substance is removed discontinuously. 
     
     
       9. The method according to  claim 1 , wherein filtering the extracted water is performed using a filtering device that uses reverse osmosis or nanofiltration, and wherein the method further comprises cleaning the filtering device using a magnetic field. 
     
     
       10. The method according to  claim 3 , further comprising cleaning the prefiltering device using a magnetic field.